First off, I really like the script! You have done a really great job with it.

I have a suggestion, though. If you plan on continuing development, you might consider putting it on github. That will allow other contributors to more easily get involved and both developers and users to see a concrete changelog. A more succinct changelog and readme might also be helpful. If you want a template for a much more complex BASH script that is already on github and implements both a changelog and readme, check out the github page for Minecraft Server Manager. (Although MSM's changelog and readme are in markdown format, you don't necessarily have to do that. In fact, most open-source projects implement their documentation in plain text. Download the apt-build source code, for example, and take a look at debian/changelog and debian/README.Debian to see an example of more standard formatting.)

If you haven't ever used git before, I suggest that you take a look at github's Introduction to Git tutorial. It is very good, in my opinion, and explains everything you will need to know to start using git.

Edit: What happened? I thought the post editor merged successive posts by the same user if they were made relatively quickly. I can still edit both posts, but even if I merge them I will still have a useless post immediately below the merged one since I can't delete posts!